Electrical signal code generating equipment



y 4, 1966 R. c. MCINTOSH 3,253,087

ELECTRICAL SIGNAL CODE GENERATING EQUIPMENT Filed April 30, 1962 2Sheets-Sheet l I L/GHT GU/DE 5 Pl/O TUCEZ L FIG. I.

May 24, 1966 R. c. M INTOSH ELECTRICAL SIGNAL CODE GENERATING EQUIPMENT2 Sheets-Sheet 2 Filed April 30, 1962 PHOTOCELL 28 FLASH LAMP FIG. 2.

United States Patent 3,253,087 ELECTRICAL SIGNAL CODE GENERATINGEQUIPMENT Ronald Campbell McIntosh and Haydn Victor Purdy, London,England, assignors to Purdy & McIntosh (Electronic Developments)Limited, London, England, a British company Filed Apr. 30, 1962, Ser.No. 191,188 Claims priority, application Great Britain, May 2, 1961,15,910/ 61 3 Claims. (Cl. 178-79) This invention relates to electricalsignal code generating equipment,

The object of the invention is to provide a simple, adjustable, andeconomical device for this purpose.

The main aspect of the invention comprises electrical signal codegenerating equipment for generating multielement electrical codesignals, comprising an array of light guides equal in number to thetotal number of elements in the multi-element code, at least one lightsource for illuminating the light guides at an input position on eachguide, an individual photo-electrical device at an output position oneach light guide, coding members each arranged to block the light pathsthrough a selection of said light guides to said photo-electricaldevices, and means for selecting one of said coding members forcontrolling the generation of the particular code signal correspondingto said selected coding member.

The invention will be described with reference to certain embodimentsshown in the accompanying drawings in which:

FIG. 1 illustrates, by way of example, and in perspective, equipment forgenerating 3-bit binary codes by means of a code card, while FIG. 2 is aperspective view of a few keys of a keyboard together with light sourcesand light-responsive devices for creating electrical signal codes undercontrol of said keys.

The equipment shown in FIG 1 utilises light guides 1 for selectivelygenerating the individual elements of a code, and a code card holder forpositioning a code card 2 so as to determine the individual codes to begenerated.

The light guides 1 can be of transparent plastic, or of glass, therebeing an individual guide for each element of a code. The opaque codecard 2 can span all the individual light guides, and have a series ofparallel vertical lines 3 of open or transparent apertures in the card.Each aperture is individual to a light guide 1 and the number anddistribution of the apertures in each line determines the code to begenerated by its use.

The code card is positioned between the light guides 1, and at least onesource of light 4 capable of illuminating all the light guides, while atsome other position on the light guides, photo-electrical devices 5, oneper light guide, are arranged to detect light transmitted via therespective light guides.

In the preferred embodiment shown in the drawing, thin bars oftransparent plastic are stacked as shown with opaque films 6 betweenthem and on the outside of the top and bottom bars, to define theindividual light guides.

On one side of the stack of guides 1 is positioned the code-card 2 in aholder (not shown) between the side of the stack and a line ofvertically-arranged tubular xenon flash lamps 4; the length of the lampsspans the height of the light-guide stack, and the lamps are positionedso that each lamp is opposite a vertical line 3 of code apertures in thecode card 2. The back edges of the guides, the near ends, and thoseportions of the front edges not covered by the code card, can bepainted, or silvered or otherwise treated to :assist in Zig-zagreflection of light rays along the light guides, Vertical grooves 73,253,687 Patented May 24, 1966 Ice of triangular cross-section can beformed in the light guides to assist the distribution of light withinthe light guide, so that light rays are reflected along the bars inzig-zag formation.

Opposite the far ends of the light guides, or at any other desired pointnot used for code transmission, and which is left clear for lightemission, are arranged lightsensitive devices 5, one opposite each guide1.

By flashing any one of the lamps 4, the corresponding binary code willbe transmitted along the light guides by internal reflections to operatea corresponding selection of light-sensitive cells at the far end of thelight guides.

Thus a static electrical signal-code generator has been provided. Thelamps can be operated by electrical signals from any suitable source. Inparticular, the lamps can be individually operated from electricalcontacts individual to, and operated by the depression of, the keys of akeyboard. The operation of the lamps can be the sole purpose of such akeyboard, or can be ancillary to the main purpose thereof which may be ateleprinter, or a typewriter, for example.

The present code-generator can be utilised to amplify the codingfacilities provided by the electrical signal code generator described inthe following description of FIG. 2 by providing electric contactsindividual to the keys of the said generator, and connecting suchcontacts to the lamps of the code generator shown in FIG. 1. The lightguides could be of any desired shape in plan which was suitable for anyparticular application.

Alternatively, the code card could be arranged for controlled movementin front of one lamp, or several lamps, so as to select any desiredcode, or group of codes, for transmission. In such a case, the lightcould be, for example, rods of small diameter or other cross-section,and could be of any length and shape, determined by the requirements ofany application. The movement of the card would be controlled in anyknown manner under control of a keyboard, or under control of electricsignals, for example. It is clear that the code card can be selectedfrom a number carrying different code combinations.

In FIG. 2, each key, one of which is shown depressed, esesntiallyconsists of a flat stamping 21 of sheet metal with two substantiallyparallel horizontal lines 22, 23, of

' holes 24 stamped along its length, the holes in the rows being equalin number and successive pairs of holes A, A; B, B; etc. in the two rowseach being vertically in line.

The keys are supported side by side in close array in any desired mannerand controlled so that when idle, the keys are all horizontally in lineso that the y holes in each row are in line and form y tunnels 27through the array of keys, thus providing an upper row 25 and a lowerrow 26 of tunnels in each row. The number y corresponds to the number ofelements or bits in binary signal code words to be formed by the keyset.

As shown, the holes 24 in the keys 21 are horizontal slots, but they maybe of any desired shape.

A row of light sources 28, y in number, which can be constituted by asingle tubular flash lamp, is disposed opposite the lower row of tunnels26 at one end of the tunnels, and a now of light responsive devices 29,one per tunnel, is disposed opposite the lower row of tunnels 26 at theother end so that light can pass through each tunnel from a light sourceto a light responsive device. The lower row of tunnels 26 thusconstitute light guides.

The purpose of the upper row of holes 25 in the keys 21 is to formbinary codes. The codes are formed by blocking out any desired selectionof holes in the upper row in any desired manner, for example, bysticking a removable opaque patch 30 over each hole to be blocked out.The patches can all be individual to a hole, or

3 patches of varying lengths can be used according to the number ofadjacent holes to be blocked.

Keys can be stamped having permanent codes formed in the upper row orholes, but by forming a standard key blank, and removably blocking outholes as required, the keys are cheap to make and the individual codescan be easily changed. The keys can, of course, generate several codessimultaneously, each controlled by at least one tunnel.

The keys are mounted so that they can be individually depressed, on acommon pivot 01' on linkages, and their movements are controlled so asto bring the upper line of holes in a depressed key into line with thelower rows of holes in the other keys, as indicated in FIG. 2, wherebythe patches on the upper row of holes on the depressed key obscure thecorresponding tunnels in the lower row of tunnels 26.

In this way, light cannot pass to the light-responsive devices at theends of the tunnels thus obscured, and the combination of operated andunoperated light-responsive devices thus formed indicates the binarycode oi the depressed key.

The light sources are preferably flash lamps operated to send pulses oflight down the unobscured tunnels when a key is operated. Alternatively,the light sources could be continuously illuminated, and the code formedby obscuring some of the tunnels: in this case, the photo-electric cellscould be rendered operative on the depression of any key.

The light-responsive devices will be wired to any suitable electricalcode responsive equipment capable of detecting in turn a succession ofcodes signalled by the depression in turn or any desired sequence ofkeys, and signalling the successive codes to any type of recording ortransmission equipment as desired. The keys are stamped from aluminium,steel, or any other suitable material. Adequate light transmission isobtained without the need for a perfect line-up of the holes forming atunnel. Neither need the key bodies be in contact: they can be spaced byabout their own width, or less. The internal faces of the slots arebright and assist light transmission by zigzag reflections through thetunnels, in addition to unimpeded light transmission.

The light transmission tunnels could be formed independently of thekeys, but apertured for the passage of obscuring prongs or the likecarried by the keys. This and any other desired method of providing arow of light tunnels and means individual to each key of a keyboard forobscuring a predetermined selection of such tunnels when depressed iswithin the scope of the invention.

In addition to the code slots in the keys, the keys can be provided eachwith at least one additional hole in the lower row, so that thedepression of any one key will obscure an additional tunnel so formed.The depression of such a key will cut off a continuously-illuminatedlight source at one end of the tunnel from a light-responsive device "atthe other end of the tunnel, thus generating a electrical signalindicating that a key has been depressed. This signal is valuahle, andits production in this way, rather than by the use or the key as anelectric contact, allows the use of uninsul ated metallic keys.

What is claimed is:

1. Electrical signal code generating equipment for generatingmulti-element electrical code signals comprising a stack of plates oflight-transmitting material, one plate per code element, meanscomprising light sources at a first position on said stack for supplyinglight to each plate in said stack, a row of-light-detecting means normalto said stack at another position thereon for responding to lightsignals from said light sources transmitted through said plates to saiddetecting devices, and code selecting means in the light transmissionpaths between said light sources and said light detecting means, whichcode selecting means are formed with rows of holes normal to said stackof plates, each row comprising a hole corresponding to each of aselection of said plates for selectively applying a particularmulti-element code signal to said light-detecting means based on amulti-element code system having as many elements as there are plates insaid stack.

2. Electrical signal code generating equipment for generatingmulti-element electrical code signals, comprising an array of basicallyidentical keyboard elements, each element having a :plurality of holestransversely therethrongh and positioned in upper and lowerapproximately parallel rows extending longitudinally of the element,said elements being positioned side by side with the holes substantiallyin alignment whereby a row of approximately horizontal lighttransmitting tunnels each having an input end and an output end aredefined by respectively positioned holes of said lower row, holeobscuring means mounted over at least one of the holes of said upper rowon each element to form tor each element a combination of unobscured andobscured holes unique to the element, said elements being movable to adisplaced position at which the holes of said upper now of the movedelement are brought into alignment with the holes of said lower rows ofthe undisplaced elements, light means positioned at the input end ofeach tunnel to project a light beam into the respective tunnel, and anindividual photoelectric device for each of the tunnels respectively,each device being positioned at the out-put end of its respective tunnelto produce an electric signal in response to the presence of lightemitted at the output of the tunnel.

3. Equipment as set forth in claim 2, wherein said hole obscuring meanscomprises opaque stickers stuck to the element over the respective holeof the element.

\ References Cited by the Examiner UNITED STATES PATENTS 2,408,75410/1946 Bush 178-79 2,438,825 3/1948 Roth 178-17 2,709,001 5/1955 Stahl23561.l2 2,953,300 9/1960 OBrian et a1 23561.12 3,017,463 1/1962Dinsmore et al. 178-79 FOREIGN PATENTS 469,809 8/1937 Great Britain.

OTHER REFERENCES IBM Technical Disclosure Bulletin, vol. 3, No. '11,

April 1961, entitled Photo Keyboard, by Lynott.

NEIL C. REID, Primary Examiner.

ROBERT H. ROSE, Examiner.

A. I. DUNN, T. A. ROBINSON, Assistant Examiners.

2. ELECTRICAL SIGNAL CODE GENERATING EQUIPMENT FOR GENERATINGMULTI-ELEMENT ELECTRICAL CODE SIGNALS, COMPRISING AN ARRAY OF BASICALLYIDENTICAL KEYBOARD ELEMENTS, EACH ELEMENT HAVING A PLURALITY OF HOLESTRANSVERSELY THERETHROUGH AND POSITIONED IN UPPER AND LOWERAPPROXIMATELY PARALLEL ROWS EXTENDING LONGITUDINALLY OF THE ELEMENT,SAID ELEMENTS BEING POSITIONED SIDE BY SIDE WITH THE HOLES SUBSTANTIALLYIN ALIGNMENT WHEREBY A ROW OF APPROXIMATELY HORIZONTAL LIGHTTRANSMITTING TUNNELS EACH HAVING AN INPUT END AND AN OUTPUT END AREDEFINED BY RESPECTIVELY POSITIONED HOLES OF SAID LOWER ROW, HOLEOBSCURING MEANS MOUNTED OVER AT LEAST ONE OF THE HOLES OF SAID UPPER ROWON EACH ELEMENT TO FORM FOR EACH ELEMENT A COMBINATION